The field of application of the invention is particularly that of gas turbine aeroengines. Nevertheless, the invention is applicable to other turbine engines, e.g. industrial turbines.
Ceramic matrix composite (CMC) materials are known for conserving their mechanical properties at high temperatures, which makes them suitable for constituting hot structural elements.
For turbine ring assemblies that are made entirely out of metal, it is necessary to cool all of the elements of the assembly, and in particular the turbine ring, which is subjected to particularly hot streams. Such cooling has a significant impact on the performance of the engine, since the cooling stream used is taken from the main stream through the engine. In addition, the use of metal for the turbine ring limits possibilities for increasing temperature within the turbine, even though that would improve the performance of aeroengines.
Furthermore, a metal turbine ring assembly deforms under the effect of hot streams, thereby changing clearances associated with the flow passage, and consequently modifying the performance of the turbine.
That is why proposals have already been made to use CMC for various hot portions of engines, particularly since CMCs present the additional advantage of density that is lower than that of the refractory metals conventionally used.
The use of ring sectors made of CMC makes it possible to reduce significantly the amount of ventilation needed for cooling the turbine ring. Nevertheless, keeping or retaining ring sectors in position remains a problem in particular in the face of differential expansion, as can occur between a metal support structure and CMC ring sectors. In addition, another problem lies in controlling the shape of the passage both when cold and when hot without generating successive stresses in the ring sectors.
Also known is Document WO 2015/191186, which discloses a turbine ring assembly.
There thus exists a need to improve existing turbine ring assemblies that make use of a CMC material in order to ensure that ring sectors are retained in position in spite of differential expansion, while also limiting the magnitude of the mechanical stresses to which the CMC ring sectors are subjected in operation.